M1A1 Abrams

Following a competition, early in 1994, the US Army Tank Automotive Command awarded General Dynamics Land Systems a US$26 million, 39 month Engineering, Manufacturing and Development Phase contractfortheHeavyAssault Bridge (HAB). Under this phase an additional two systems, now called the Wolverine, have been built, with trials starting in June 1996.

Late in 1996, General Dynamics Land Systems was awarded a contract by the US Army for an additional six Heavy Assault Bridge (HAB) systems based on a modified M1 MBT chassis.

Two prototype HAB have already been delivered for extensive user trials under the Engineering Manufacturing Development (EMDII) Phase. The major subcontractor for the HAB is MAN of Germany which developed the Leguan bridge and its associated laying system.

Total US Army requirement, funding permitting, is for 601 HAB systems on the M1 MBT chassis which will be conversions of existing 105 mm M1 gun tanks and not new build chassis. The latter will however be brought up to the latest M1A2 digital standard for fleet commonality by US Army depots which will then deliver these to the Lima Army Tank Plant.

The HAB is also known as the Wolverine and consists of an MLC 70 (Military Load Class) horizontally launched bridge integrated onto a modified M1 MBT chassis. When opened out, the bridge is 26 m long and can be used to span gaps of up to 24 m.

The new HAB has a number of advantages over the current US Army scissors-type Armoured Vehicle Launched Bridge (AVLB) based on the old M48/M60 MBT chassis.

Not only does it have a higher road speed, improved cross-country mobility and greater armour protection but as the bridge is laid horizontally it is more difficult to detect and the complete system is more survivable.

The computer-controlled automatic launch system allows the driver/operator or commander to launch or recover the bridge in under 5 minutes under complete armour protection using a single joystick.

Mounted at the front of the M1 chassis is a blade which is lowered to the ground to stabilise the system while the bridge is being launched. The blade can also be used for bridge cleaning and light dozing.

There are no hydraulics or electronics on the bridge. A separate Launch Power Unit (LPU) is fitted to supply hydraulic power for spade and actuators on the launch mechanism with back-up capability from the chassis power pack-driven pump.

The HAB is unarmed but is fitted with a multi-spectrum smoke grenade system and a fog-oil-based obscuration reinforcing system.

An NBC system is fitted as standard and there are also separate automatic fire extinguishing systems for the crew, chassis power pack and launch power unit.